1. Field of the Invention
The present invention relates to a new compounds a metal extractant including the new compound; a method for extracting zirconium or at least one of palladium and platinum, using the metal extractant; a method for recovering at least one of palladium and platinum and recovering zirconium, using the metal extractant; and a method for separately extracting palladium and platinum, using the metal extractant.
2. Description of the Related Art
Metals such as cobalt (Co), titanium (Ti), nickel (Ni), vanadium (V), chromium (Cr), manganese (Mn), zinc (Zn), yttrium (Y), zirconium (Zr), hafnium (bat), niobium (Nb), cadmium (Cd), lanthanum (La), cerium (Ce), neodymium (Nd), europium (Eu), terbium (Tb), mercury (Hg), uranium (U), platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (Os), barium (Ba) and aluminum (Al) are included, in the 31 minerals defined by the Rare Metal Division of the Mineral Resources Subcommittee, Advisory Committee for Natural Resources and Energy of Ministry of Economy, Trade and Industry, and these metals are indispensable to our lives and are used for a variety of products including present-day precision instruments, such as automotive catalysts, fuel cells and ultrahigh-strength magnets.
Among these metals, palladium and platinum are used as materials for precision instruments, dental materials, etc. and zirconium is used for piezoelectric elements, condensers, etc. Palladium, platinum and zirconium are metals that are present in the smallest amounts in the Earth's crust, and thus their prices have been increasing amid the recent competition among countries to procure resources. Accordingly, in view of stable supply of resources and protection of the environment, methods for recycling palladium, platinum and zirconium have been proposed.
Among the methods for recycling palladium, platinum and zirconium, there is, for example, a method wherein an extractant for extracting palladium, platinum and zirconium is added to an aqueous solution containing palladium, platinum and zirconium so as to extract the palladium, the platinum and the zirconium, and a variety of extractants for this sort of purpose have been developed and utilized (refer to Japanese Patent Application Laid-Open (JP-A) Nos. 2007-239066 and 2007-239088).
However, the selectivity with which any of palladium, platinum and zirconium is extracted and the extraction rate thereof are not satisfactory enough; accordingly, provision of an extractant capable of extracting any of these with higher selectivity and at a higher extraction rate is being demanded, and provision of an extractant having selectivity for platinum that has a particularly wide range of uses, among the above-mentioned metals, is being highly demanded.
Thus, in reality, swift development of a new metal extractant capable of selectively extracting any of palladium, platinum and zirconium is being strongly demanded.